Planning and Building Wood Deck Stairs with Landing

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How to plan and build a wood deck stairs and landing with design diagrams. The new deck stairs were built exclusively with 1/2 inch galvanized bolts, Simpson Strong-Tie metal connectors and wood screws. No nails were used! Photo of the new deck stairs:

Build New Wood Deck Stairs and Landing

Build New Wood Deck Stairs and Landing

Table of Contents

  1. Planning and Building Wood Deck Stairs with Landing (you are here)
  2. Tear Down Old Wood Deck Stairs and Landing
  3. Remove Wood Deck Stair Landing Support Posts and Concrete Footers
  4. Build Deck Stair Landing: Pour Concrete Footers and Install 6×6 Posts
  5. Deck Stair Landing: Saw Post-to-Beam Support Notches
  6. Deck Stair Landing Beam and Joist Framing
  7. Deck Stair Stringer Hanger Board and Simpson Strong-Tie LSCZ Stringer Connectors
  8. Install Wood Deck Stair Stringers and 4×4 Newel Posts
  9. How to Frame a Wood Deck Stair Landing
  10. Build Wood Deck Stairs – Layout Solid and Sawn Stringers
  11. How to Install Deck Stair Stringers and Treads
  12. Build Wood Deck Stairs and Landing – Completed Job Photos

Planning and Building Wood Deck Stairs with Landing

Poorly Built Wood Deck and Stairs

My house was built in the year 2000 before the modern Wood Deck Building Code was enacted. It had many construction deficiencies which I’ve since corrected. The current problem is the stairs are rickety may collapse. They need to be torn down and rebuilt from scratch. Another problem is the original stairs lacked an interior guard rail on the upper flight, instead the builder installed long 2×2 inch pickets:

Old Wood Deck and Stairs Built in 2000

Old Wood Deck and Stairs Built in 2000

The lower stairs are visibly sagging. I jacked the upper stairs (which were sagging on the right) and installed a double 2×4 ledger to level and support the stair stringers as a temporary measure. The prior homeowner tried fixing the problem by inserting shims between 6×6 support post and landing:

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Sagging Wood Deck Stairs Caused by Deck Post Footer Movement

New Wood Deck Stairs and Landing

The wood deck and stairs after extensive rebuilding. Everything with a lighter redwood stain has been rebuilt. Darker wood is where the stain soaked into bleached lumber that was never sealed by the former homeowner:

Rebuilt Wood Deck Stairs Landing Guard Rail and Knee Bracing

Rebuilt Wood Deck Stairs Landing Guard Rail and Knee Bracing

View of the stairs from upper flight. The 2014 IRC Prescriptive Deck Code (see Sheet 20) requires a handrail with end returns. I installed a Fortress Railing Products 1-1/2 inch diameter black aluminum handrail. It was expensive (about $500 in materials for my stairs) but worth it and easy to install:

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Rebuilt Wood Deck Stairs with Fortress Aluminum Handrail

The lower stairs were built with two solid stringers cut from 2×16 No. 1 grade Pressure Treated boards. Due to the length and height of the upper stairs, these were made with two solid outer stringers and a sawn middle stringer cut from 2×16 boards for extra strength. The sawn middle stringer is reinforced with a 2×4 screwed to the bottom edge which makes it look thicker:

Rebuilt Wood Deck Stairs and Landing

Rebuilt Wood Deck Stairs and Landing

I filed a Building Permit and obtain all inspections and final sign-off from the Building Inspector. I did all the work myself with help from my son. The materials cost was about $4,000 which seems expensive (the aluminum handrail was $500) but the concrete, concrete mixer tool rental, lumber, galvanized bolts and Simpson Strong-Tie connectors, wood preservative and stain adds up quickly.

Wood Deck Stair and Landing Design Diagram

Building deck stairs seems like a straightforward job but the layout can be tricky. I created a scale drawing in Microsoft Visio after making careful measurements:

Wood Deck Stairs with Landing Planning and Construction Diagram

Wood Deck Stairs with Landing Planning and Construction Diagram

The critical dimensions are Rise (vertical stair height) and Run (horizontal stair length). To calculate the Rise and Run the following measurements are necessary:

  • Height of the deck to the stair landing: Upper Stair Rise = 9 ft
  • Horizontal distance from the deck edge to the landing: Upper Stair Run = 9 ft 7-3/4 in
  • Height of the landing above the concrete step: Lower Stair Rise = 5 ft 9-1/4 in
  • Horizontal distance from the edge of the landing to the concrete step: Lower Stair Run = 6 ft 9-1/2 in

The Deck Code allows a maximum 7-3/4 inch Riser height (distance from one step to the next) and a 10 inch minimum stair tread width. Running the numbers on the original deck stairs revealed the builder miscalculated and cut the stringers too short which barely reached the landing. The difference is my stringers are longer than the old stringers and will rest solidly on the landing for proper support.

To calculate the number of steps required for a given Rise and Riser Height:

Number of Steps = [total Rise in inches] divided by [Riser height in inches]

  • 13.935 = 108 inches (or 9 ft) / 7.75 inches

Which is 13 full height 7-3/4 inch steps with a shorter 7.25 inch (= .935 * 7.75 after rounding to two decimals) first step (landing to 1st tread). The stringer layout for the upper stair solid outer strings is illustrated in the following diagram:

Wood Deck Stair Solid Stringer Diagram

Wood Deck Stair Solid Stringer Diagram

The Run for 13 stair stringer steps (see the above diagram) is 13 Steps * 10 inch Tread per Step = 130 inches, or 10 ft 10 in. Reality Check: The stringer horizontal distance spanned is 10 ft 10 in which is greater than the 9 ft 7-3/4 in measurement between the Landing and the Deck, so the stringer will be long enough for the job.

Solid Deck Stair Stringers

The stair treads will be supported by Simpson Strong-Tie TA9Z-R ZMax Staircase Angles because I’m using solid stringers. For treads, I used WeatherShield 2 in. x 12 in. x 4 ft. Pressure-Treated Wood Step-Tread available at Home Depot. I had to visit three different stores in my area and pick through the shelves to find decent quality ones without warps, splits and large knots.

The normal way of laying out a solid stair stringer is to attach stair gauges to a carpenter’s square and trace the steps. I’ll do this but also made a scale drawing in Microsoft Visio which I’ll use to double check my work during construction. It’s clear that 13 feet 7 inch long stringers will require 16 feet long 2×12’s:

Wood Deck Stair Solid Stringer Measurements Diagram

Wood Deck Stair Solid Stringer Measurements Diagram

The notch in the stringer foot where it rests on the landing is to accept a 2×4 base plate that is screwed to the landing. The base plate resists the forward thrust forces when the stringer and stairs flexes under load.

Sawn Deck Stair Stringer

The upper stairs will have sawn middle stringer for extra strength. “Sawn” means the steps are cutout. Because the treads are mounted on top of the sawn stringer, it must be mounted 3-5/8 inches lower than the solid stringers against the deck joist, or in my case the stringer hanger board. Laying out the sawn stringer on the computer provided this critical insight which is easy to miss on the job site:

Wood Deck Stair Sawn Stringer Diagram

Wood Deck Stair Sawn Stringer Diagram

Deck Stair Landing

A deck stair landing must conform to the “free-standing deck” code requirements. The following diagram (remove H2.5AZ) shows the 4 ft wide x 10 ft long basic layout and materials list:

Wood Deck Stair Landing Framing and Materials Diagram

Wood Deck Stair Landing Framing and Materials Diagram

At 10 feet long, the new landing is about 2 feet longer than the original to make it feel a little more roomier. I couldn’t make the landing wider than 4 feet because it’s boxed in between two 6×6 deck support posts at the front and back. Details such as 2×6 knee bracing, interior blocking and guard rails are omitted as these are simple to inventory later with paper and pencil.

This project is continued in Tear Down Old Wood Deck Stairs and Landing.

Thanks for reading,

Bob Jackson

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